Surgical sliding shaft instruments of the type described hereinabove in the form of bone punches for example are known. They are constructed in such a manner that the two shaft parts forming the sliding shaft are guided directly upon one another. For this purpose, there are provided so-called internal guide elements which form the guidance device and which are arranged or formed on the surfaces of the shaft parts that rest upon one another. The two shaft parts, which are also referred to as an upper slide part and a lower slide part, abut each other directly. This, however, has the disadvantage that when cleaning or even when using the instrument, fluid can be sucked in between the shaft parts that abut each other. It is practically impossible to remove this fluid without dismantling the instrument.